Available online 1 April 2015
Numerous studies have demonstrated deterioration of orthodontic treatment outcome postretention; however, few studies present results in cases still in retention long term. The aim of the present study was to evaluate orthodontic treatment outcomes in patients with teeth still in retention at 10 years post-treatment.
This longitudinal study enrolled 108 children who received bonded lingual retainers after treatment with a full fixed appliance. Retainer extension and morphologic stability, as measured by weighted peer assessment ratings (wPAR), were recorded at pretreatment (t0), immediately post-treatment (t1), 5 years post-treatment (t5), and 10 years post-treatment (t10). The t10 results were compared with those from an untreated control group matched on age and sex. Post-treatment stability was additionally tested for correlation to age, sex, malocclusion, and extraction therapy.
At the group level, there was a significant mean reduction in wPAR of 74% at t10 (P < 0.001). Additionally, the mean wPAR was significantly better than was that in the control group. At the patient level, 57% of patients were categorized as “greatly improved.” The only factor that could be correlated to post-treatment changes (from t1 to t10) was the presence of at least one bonded retainer (P < 0.05).
A “high standard orthodontic treatment outcome” could be maintained 10 years post-treatment by keeping the bonded retainers in both the upper and lower arches. Orthodontic patients expect the aesthetics to be maintained over time. The results from this study, that bonded lingual retainers maintain the orthodontic treatment result for 10 years, are valuable information for the clinician when giving the patients advice and recommendations regarding retainer maintenance.